In SPEC-1467, we talk about to detach Homescreen application like launcher application.

This issue will commit the source code.

For homescreen-2017
    Delete Home QML file from main.qml.
    Change Home shortcut icon to launcher.

For launcher
    Move Home QML file to Launcher.qml.
    Use qlibhomescreen instead homescreenhandle.

These are some problems remain.
1 Start application in launcher icon area will not block shortcut area and launcher icon area. 
2 Start application in shortcut icon area will not block launcher icon area.
Need more improvement for homescreen-service, homescreen and launcher. SPEC-1497